The Jazz Age is in full swing, but it's passing Casiopea Tun by. She's too busy scrubbing floors in her wealthy grandfather's house to do anything more than dream of a life far from her dusty, small town in southern Mexico. But when Casiopea opens a curious chest in her grandfather's room, she accidentally frees an ancient Mayan god of death. He offers her a deal: if Casiopea helps him recover his throne from his treacherous brother, he will grant her whatever she desires. Success will make her every dream come true, but failure will see her lost, forever. Armed only with her wits, Casiopea begins an odyssey that will take her from the jungles of Yucatán to the bright lights of Mexico City and deep into the darkness of Xibalba, the Mayan underworld.